Technical Field
The present disclosure relates to an occupant protection system.
Related Art
A head rest attached to a seat in a vehicle and equipped with a built-in airbag of an airbag device is known (see Japanese Patent Application Laid-open (JP-A) No. H8-175309). In its inflated state the airbag with which the head rest is equipped expands in a substantially forward direction from the sides of a head portion.
Furthermore, a head rest airbag that is housed in a head rest and configured to receive a supply of gas at the time of a side impact to become inflated and deployed, before a curtain airbag, on both vehicle width direction sides of the head of an occupant is also known (see JP-A No. 2015-13553).
This airbag has a duct portion, which inflates in back of the head, and an inside bag portion and an outside bag portion, which inflate on both sides of the head. The duct portion is coupled by tethers to the inside bag portion and the outside bag portion.
In the configuration of JP-A No. H8-175309, it is difficult to stabilize the deployment behavior of the airbag because the airbag becomes inflated and deployed alone from the sides of the head rest. In the configuration of JP-A No. 2015-13553, the head rest airbag is effective for a relatively small capacity head rest airbag used in combination with a curtain airbag, but it is difficult to stabilize the deployment behavior of the head rest airbag if the capacity of the head rest airbag is increased.